(1) Field of the Invention
This invention relates to agriculture and more particularly to the application of herbicide.
(2) Description of the Prior Art
The use of herbicides for the control of weeds is widespread in agriculture today. Generally pre-plant and pre-emergent herbicides may be broadcast over fields without injury to crops. Few herbicides, however, are specific for weeds alone and so once a crop has emerged it is necessary to treat only the weed with herbicide to avoid killing the crop plant. The problem is aggravated in the western regions of the United States which have high temperatures, low humidity and dry winds. With the application of herbicides by a damp applicator, there is a very high evaporation rate from the applicator so that it is necessary to continually replinish the fluid supply of herbicide to the applicator.
Selective means for the dispensation of herbicides have recently come to be known. These methods of treating weeds have become increasingly important as "hoe hands", who manually kill weeds are unavailable. Also, general distribution of even pre-plant or pre-emergent herbicide stunts the growth of many crops.
Methods of selectively applying herbicides to weeds after the emergence of a crop have largely been very involved mechanically or ineffective. Heretofore, no simple method for selective application of herbicides to weed after emergence of crops has been known in the art.
In addition to agricultural weed killing, there exists a problem for governmental units killing weeds and tall grasses along the right-of-way of public roads. Often the roadsides are sloped, and sometimes sloped sharply away from the roadway. Therefore, the vehicle carrying any applicator must necessarily operate with one side of the applicator far lower than the other side of the applicator.
Before filing this application, applicant caused a search of the prior art to be made at the United States Patent and Trademark Office. That search revealed the following patents:
U.S. Pat. No. 1,109,060, Griffin PA1 U.S. Pat. No. 1,523,590, Hartshorn PA1 U.S. Pat. No. 1,764,952, Hay PA1 U.S. Pat. No. 1,818,369, Watson PA1 U.S. Pat. No. 2,123,988, Corley PA1 U.S. Pat. No. 2,935,818, Crane PA1 U.S. Pat. No. 3,021,642, Ewing PA1 U.S. Pat. No. 3,077,701, Osmun PA1 U.S. Pat. No. 3,320,694, Biron PA1 U.S. Pat. No. 4,019,278, McKirdy
EWING discloses a solid sheet-like wick extending from the bottom of a header with a few inches of head thereon.
HAY disclosed a boll weevil poisoner having wet strands hanging from a chamber with liquid therein.
WATSON shows a series of strands hanging down vertically from an axial pipe which distributes the liquid to it.
While the other patents cited are thought by applicants to be of little interest with respect to their invention, other workers in the field are continuing to work in this area. Reference is particularly made to our prior patent application, wherein work done by the United States Department of Agriculture, and particularly Dr. J. E. Dale is described. Applicants believe that Dr. Dale has filed a U.S. Patent Application, Ser. No. 969,036 entitled ROPE WICK APPLICATOR.
Also within recent months, certain publications in farm literature have been published, however, none of these prior publications were more than one year before this invention or before the invention.